"Pandora" is the fourth episode of Series 3 and the 23rd episode overall.

This episode primarily focuses on Pandora Moon, who has to cope with the sudden absence of her new boyfriend Thomas Tomone along with her slowly fracturing friendship with Effy Stonem.

Plot

At the Stonem household, Pandora laments the loss of her boyfriend, Thomas, who recently returned to his home country, the Democratic Republic of Congo. At breakfast, Effy's father, Jim, discovers his wife's infidelity when his boss, Steve, arrives at the house and declares his love for Anthea. Effy is near tears as Jim immediately decides to move out, but confirms that she will still be attending Pandora's slumber party, secretly hoping to get "totally fucked." After a brief run-in with Katie and her boyfriend, the three girls arrive at Pandora's house for the party and meet her neurotic mother, Angela. Disappointed by the lack of boys, drugs and alcohol mandated by Angela's strict supervision, Katie spikes the brownies that they make with MDMA. As Naomi and Emily arrive together, Naomi urges Emily to admit that she is gay, but Emily denies it. All of the girls indulge in the brownies and Pandora is unhappy to see her mother's behavior grow increasingly erratic. After Angela is carried into a bedroom to sleep, Pandora locks herself in the bathroom, upset about Thomas's departure and angry with Effy, who she believes spiked the brownies.

Outside, Cook and JJ try to sneak into the girls' party. Cook enters the house through a window, but accidentally locks himself inside a wardrobe. After calling Freddie for help, JJ goes into the house by himself and sees Emily and Naomi kissing. Katie, too, witnesses the pair kissing, but is interrupted when her footballer boyfriend, Danny Guillermo, and dozens of his friends arrive at the house to crash the party. Effy finds Cook, and they have sex in the wardrobe. They fall through the wall into the next room and find a DVD which shows Angela having sex with her elderly neighbour, Martin. Freddie comes to take JJ home and confronts Effy about leaving Pandora for Cook. As he leaves, so does Effy.

By the time Pandora comes out of the bathroom, Cook is the only person left at the house. Together they play Twister, which Pandora had hoped to do all along. Cook offers to have sex with her, and they spend the night together. Effy visits Pandora the next morning, and sees Cook share a kiss with her as he leaves. Feeling hurt, she confronts Pandora, but to no avail, as Pandora is slightly empowered after losing her virginity. Pandora defiantly tells Effy that Cook, due to his promiscuity and impulsive, carnal behavior, belongs to no one. Effy appears to understand, and makes no rebuttal. Suddenly, Thomas appears and runs up to Pandora, and she sobs in his arms as a thoughtful Effy looks on.

Note: The music tracks listed below only refer to the music featured in the episode's initial airing. Many of the music tracks featured in this episode have been substituted for alternative tracks either for the BBC America airing or for both the US and UK home media release of Series 3.